18650 vs 21700 battery packs.

[Retrorockit]

I got the 21700 in a Hailong Mega Shark pack with 24Ah. The bracket was a PITA. I've seen newer ones that look much better. So you can go a bit bigger in 21700 if you have room for it.

[jaaklucas]

A year and a half ago my Hailong 18650 pack was getting weak after 18000K, 4 1/2 years so I got to looking for a new pack. I found that the 2170s had better stated density so why not. My battery pack guy here made me a 48V 19.5 hour with 2170s in a Reention downtube case. Its a little wider than the 18650s Hailong pack. Pretty much the biggest downtube battery enclosure before a triangle pack. I asked for the Tesla 2170s which he had. Nice pack, no issues, lots of umph.

[Retrorockit]

i found this site having a Black Friday 50% off sale on some of their 21700 stufff. I'll just link to the thread here.

https://electricbike.com/forum/forum/for-sale/deals-and-finds-on-the-web/157799-black-friday-battery-sale

[stts]

waste of time

[Retrorockit]

There is a tropical storm moving in. Lots of headwinds. 20mph and gusting 25-30mph. I decided to take my longer 36mile ride and see what happened. Went out and 1/2 way back. Sat out the first rain squall at my favorite Irish pub. Finished the ride in a light drizzle. Skipped my 30 mph runs at the end. Not needed due to light traffic. Got home with a flat battery but still PAS 1 powered, I did this as a battery test. The test was a success and so was the battery. I thought I might have more than this left, but it wasn't dead and I WAS trying to stress it. PAS 3 and 4/5 into the wind where normally I'm PAS2
This is probably my last ride for the next few days. This is expected to be a hurricane when it lands a little north of where I am. I'm on the soft side of it, so not too worried.

[Retrorockit]

I guess this is how I got there.
https://www.greenway-battery.com/new...tery-1959.html

[Retrorockit]

It's often followed by rain.
I suppose this thread could be considered as being about the pros and cons of getting a 24Ah battery. 21700 cells are just how I came to own one.
It's a very nice thing to have for me, and might give an extra years useful life making it cost effective. Time will tell.

[AZguy]

Strong wind sux

Enough said lol

[Retrorockit]

I'm on normal sized 35psi street tires and paved roads. I can make the theoretical numbers if there is no wind and I don't make 30+mph runs every now and then.
Before I wouldn't raise the assist level for headwinds, just ride slower and pedal harder to make my miles. Now I just turn up the assist to maintain my normal speed. I'm not necessarily doing less work, just fewer compromises.Almost none actually.
A ride to the beach can involve riding on busy road into a 20mph headwind all the way @ 25mph. PAS4/5. 24Ah comes in handy then. So does the BBSHD

[AZguy]

FWIW the range of Wh/mi that I've gotten through the entire life of my electric bike riding is a high of 25.9 (It's very unusual for me to exceed 20) and a low of 6.8... typically I'm in the 12-17 range, likely about 90% of my rides are in that... 20Wh/mi would be a very safe and conservative budget for me and frankly I could count on a lot less just by riding style...

Clearly, YMMV ;-}

[Retrorockit]

I saw your formula for range Wh/20=Miles. So here it is 48V.x24Ah=1152Wh/20=57.6 miles.
So a 45 mile ride with headwinds and an occasional top speed run are all in a days work.
My original 18650 battery 48Vx17.5Ah=840Wh/20=42miles. Obviously some compromises would have to be made along the way.
30 mile range was realistic for my conditions.
3 year old battery 48Vx12Ah=576Wh/20=28.8 miles.
In my world a 22 mile ride to lunch and back was about it towards the end.

[calfee20]

2170's are available inside Dewalt 6 amp Batteries. I bought a stupid amount of them. Maybe I will start to work on them if I can get my other million projects done.

[Retrorockit]

It looks like no one in the US wants to offer a 48V 24Ah,40A. Mega Shark 21700 battery any more. The guy listed above stops at 20Ah. I doubt if I have the only one, but it's the only one I've seen for sale. The 21700 really comes into it's own at the end of a long ride.Especially if I've been fighting 20mph headwinds both ways.
Nothing wrong with my old 17.5Ah 18650 battery when new. But 3 years old it was maybe 12Ah.and probably not making it's whole 30A either, or not for long anyway. If after 3 years this is still making 16Ah and 30A I'll be real happy.

[AZguy]

Engineering isn't about exact, it's about being close enough

[stts]

waste of time